Electrolyte containing additive and lithium metal secondary battery

An electrolyte and additive technology, used in secondary batteries, non-aqueous electrolyte batteries, lithium batteries, etc., can solve the problems of poor battery cycle life, unstable lithium electrode interface, etc., to improve stability, cycle stability and coulombic Significant increase in efficiency and effect of improving cycle stability

Active Publication Date: 2022-04-05
NANKAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The non-uniform deposition of lithium metal is one of the main reasons for the ins

Method used

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  • Electrolyte containing additive and lithium metal secondary battery
  • Electrolyte containing additive and lithium metal secondary battery
  • Electrolyte containing additive and lithium metal secondary battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Lithium metal secondary battery electrolyte containing additives, the lithium salt is lithium bisfluorosulfonimide LiFSI, the solvent is ethylene glycol dimethyl ether DME and 1,3-dioxolane DOL, and the additive is perfluoro(2- Methyl-3-oxaacetic acid) Lithium. Its preparation method is: mix the solvent ethylene glycol dimethyl ether DME and 1,3-dioxolane DOL at a volume ratio of 1:1, and then add lithium salt lithium bisfluorosulfonimide LiFSI at a concentration of 0.7 mol / L. Finally, add additives to make the concentration 100 mmol / L. The above-mentioned additives were not included in the comparative example.

[0034] Load 2.0 mg / cm2 per unit area 2 The pole piece of lithium titanate was used as the positive electrode, and the amount of electrolyte added was 40 μL, and the charge and discharge test was carried out at a rate of 1C. The test results show that the battery using the additive-containing electrolyte still has a capacity retention rate of more than 90% ...

Embodiment 2

[0036] Lithium metal secondary battery electrolyte containing additives, the lithium salt is lithium bistrifluoromethanesulfonimide LiTFSI, the solvent is triglyme TEGDME and 1,3-dioxolane DOL, and the additive is perfluorinated Ammonium (2-methyl-3-oxaacetic acid). The preparation method is as follows: the solvent triethylene glycol dimethyl ether TEGDME and 1,3-dioxolane DOL are mixed at a volume ratio of 1:1, and then lithium salt LiTFSI is added to the concentration of 1.9 mol / L. Finally, add perfluoro(2-methyl-3-oxaacetic acid) ammonium additive to make the concentration 20 mmol / L. The above-mentioned additives were not included in the comparative example.

[0037] The lithium titanate loading per unit area of ​​the positive electrode is 3.0 mg / cm 2 The electrode piece was added with 40 μL of electrolyte, and the charge and discharge test was performed at a rate of 1C. The test results show that the battery using the additive-containing electrolyte still has a capacity ...

Embodiment 3

[0039] Lithium metal secondary battery electrolyte containing additives, the lithium salt is lithium hexafluorophosphate LiPF 6 , the solvent is ethylene carbonate EC and dimethyl carbonate DMC, and the additive is lithium perfluoropropyl polydimethyl carboxylate. Its preparation method is: mix the solvent ethylene carbonate EC and dimethyl carbonate DMC at a volume ratio of 1:1, and then add lithium salt lithium hexafluorophosphate LiPF 6 , the concentration is 1.1mol / L. Finally, add perfluoropropyl lithium polydimethylcarboxylate additive to make the concentration 0.2 mol / L. The above-mentioned additives were not included in the comparative example.

[0040] The lithium titanate loading per unit area of ​​the positive electrode is 4.6 mg / cm 2 The electrode piece was added with 40 μL of electrolyte, and the charge and discharge test was performed at a rate of 1C. The test results show that the battery using the additive-containing electrolyte still has a capacity retentio...

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Abstract

The invention relates to an electrolyte containing an additive and a lithium metal secondary battery. The electrolyte additive is selected from one or more of perfluoropolyether-based surfactants as shown in a formula I; wherein M is Li, Na, K or NH4, X is COO or SO3, and the polymerization degree n is 0-100. The perfluoropolyether-based surface active agent is added, so that the distribution of a double-electrode-layer structure on the interface of lithium metal and electrolyte is changed, the dynamic step of lithium ion deposition is influenced, the interface stability and deposition quality of the lithium metal are improved, and the lithium metal secondary battery has longer cycle life.

Description

technical field [0001] The invention belongs to the technical field of batteries, in particular to an additive-containing electrolyte and a lithium metal secondary battery. Background technique [0002] Lithium metal has an ultra-high theoretical specific capacity (1860 mAh / g) and an extremely low electrochemical potential (–3.04 V vs. SHE). Lithium metal secondary batteries with lithium metal as the negative electrode are considered to be an upgrade of lithium-ion batteries. A new generation of high energy density electrical energy storage devices. [0003] At present, the main obstacle restricting the large-scale commercial application of lithium metal secondary batteries is the instability of the metal lithium / electrolyte interface. Continuous consumption of electrolyte, increase of interface impedance, etc. The non-uniform deposition of metallic Li is one of the main reasons for the instability of Li-electrode interface and the poor cycle life of batteries. Therefore,...

Claims

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Application Information

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IPC IPC(8): H01M10/0567H01M10/052
CPCY02E60/10
Inventor 高学平王宇旸刘胜李国然
Owner NANKAI UNIV
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